Induction heating apparatus

ABSTRACT

An induction heating apparatus has a magnetic circuit which is capable of passing an alternating magnetic flux, created by an exciter operated under a commercial frequency, through a nonmagnetic high conductive plate to a ferromagnetic material so as to result in heating the ferromagnetic material due to the generation of eddycurrents within the high conductive plate. The induction heating apparatus may comprise an induction heating cooking apparatus wherein the iron cooking vessel has an outer copper or aluminum plate secured to the bottom surface thereof.

Hibino et al.

[ Dec. 23, 1975 INDUCTION HEATING APPARATUS 3,530,499 9/1970 Schroeder 219/1049 3,684,853 8/1972 Welch et al [75] Invelltorsz th f 3,786,222 1/1974 Harnden 219/1049 asa ml wamo 0, am, 0 Japan FOREIGN PATENTS OR APPLICATIONS [73] Assignee: Mitsubishi Denki Kabushiki Kaisha, 1,157,711 7/1969 United Kingdom 219/1049 Tokyo, Japan [22] Filed: Nov. 12, 1974 Primary Examiner-Bruce A. Reynolds Attorney, Agent, or Firm-Oblon, Fisher, Spivak, [211 App]' 523ll3 McClelland & Maier Related US. Application Data [63] Continuation of Ser. No. 356,386, May 2, 1973,

abandoned. [57] ABSTRACT [30] Foreign Application Priority Data An induction heating apparatus has a magnetic circuit M 2 1972 J 47 4411'7 which 1s capable of passing an alternatmg magnetic J T 1972 Japan 4 flux, created by an exciter operated under a commery 8 1972 7'72279 cial frequency, through a non-magnetic high conducapan 1873 tive plate to a ferromagnetic material so as to result in heating the ferromagnetic material due to the genera- 219/ 33 92232 tion of eddycurrents within the high conductive plate. [58] Fi d S 79 1O 67' The induction heating apparatus may comprise an ine 0 12/9 F 5 duction heating cooking apparatus wherein the iron cooking vessel has an outer copper or aluminum plate References Cited secured to the bottom surface thereof.

UNITED STATES PATENTS 12 Claims, 56 Drawing Figures 1,975,437 /1934 Sorrel 2l9/l0.49

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1. INDUCTION HEATING APPARATUS COMPRISING: AN IRON CORE EXCITER HAVING A COVER PLATE AND HAVING AN IRON CORE EXCITATION WINDING HAVING A WINDING PITCH FOR GENERATING A LOW FREQUENCY ALTERNATING MAGNETIC FIELD, A FERROMAGNETIC ELEMENT DISPOSED ADJACENT TO THE EXCITER, A NON-MAGNETIC HIGH CONDUCTIVE ELEMENT JOINED TO THE FERROMEGNETIC ELEMENT AND INTERPOSED BETWEEN THE EXCITER AND THE FERROMAGNETIC ELEMENT AND SUPPORTED BY THE COVER PLATE FOR THE EXCITER TO FORM A GAP BETWEEN THE EXCITER AND THE HIGH CONDUCTIVE ELEMENT, THE IRON CORE EXCITER GENERATING ALTERNATING MAGNETIC FLUX PASSING FROM THE EXCITER THROUGH THE HIGH CONDUCTIVE ELEMENT TO THE FERROMAGNETIC ELEMENT TO INDUCTIVELY HEAT THE HIGH CONDUCTIVE ELEMENT, THE EXCITATION FREQUENCY BEING 60 HZ, THE GAP BEING 5 MM, THE WINDING PITCH BEING 80 MM, AND THE HIGH CONDUCTIVE ELEMENT BEING COPPER WITH A THICKNESS OF 0.3 MM TO ACHIEVE THE MAXIMUM EFFECTIVE RESISTANCE.
 2. Induction heating apparatus in accordance with claim 1 wherein the high conductive element is copper with a thickness of 1.5 mm to achieve zero time-average electromagnetic force.
 3. Induction heating apparatus in accordance with claim 1 wherein the gap is 2.5 mm and the high conductive element is copper with a thickness of 0.15 mm to achieve the maximum effective resistance.
 4. Induction heating apparatus in accordance with claim 1 wherein the gap is 2.5 mm and the high conductive element is copper with a thickness of 1.7 mm to achieve zero time-average electromagnetic force.
 5. Induction heating apparatus in accordance with claim 1 wherein the winding pitch is 120 mm and the high conductive element is copper with a thickness of 0.14 mm to achieve the maximum effective resistance.
 6. Induction heating apparatus in accordance with claim 1 wherein the winding pitch is 120 mm and the high conductive element is copper with a thickness of 1.1 mm to achieve zero time-average electromagnetic force.
 7. Induction heating apparatus in accordance with claim 1 wherein the high conductive element is aluminum with a thickness of 0.5 mm to achieve the maximum effective resistance.
 8. Induction heating apparatus in accordance with claim 1 wherein the high conductive element is aluminum with a thickness of 2.4 mm to achieve zero time-average elctromagnetic force.
 9. Induction heating apparatus in accordance with claim 1 wherein the gap is 2.5 mm and the high conductive element is aluminum with a thickness of 0.24 mm to achieve the maximum effective resistance.
 10. Induction heating apparatus in accordance with claim 1 wherein the gap is 2.5 mm and the high conductive element is aluminum with a thickness of 2.7 mm to achieve zero time-average electromagnetic force.
 11. Induction heating apparatus in accordance with claim 1 wherein the winding pitch is 120 mm and the high conductive element is aluminum with a thickness of 0.2 mm to achieve the maximum effective resistance.
 12. Induction heating apparatus in accordance with claim 1 wherein the winding pitch is 120 mm and the high conductive element is aluminum with a thickness of 1.7 mm to achieve zero time-average electromagnetic force. 